1. Field of the Invention
The present invention relates generally to an extrusion process to produce hollow pellets, wherein an insert is placed in the die holes of an extrusion die, about which is extruded the molten material to form those hollow pellets.
2. Description of the Prior Art
Pelletization equipment and its use following extrusion processing has been introduced and/or utilized in applications by the assignee for many years as is exemplified by prior art disclosures including U.S. Pat. Nos. 4,123,207; 4,251,198; 4,500,271; 4,621,996; 4,728,176; 4,888,990; 5,059,103; 5,403,176; 5,624,688; 6,332,765; 6,551,087; 6,793,473; 6,824,371; 6,925,741; 7,033,152; 7,172,397; US Patent Application Publication Nos. 20050220920, 20060165834; German Patents and Applications including DE 32 43 332, DE 37 02 841, DE 87 01 490, DE 196 42 389, DE 196 51 354, DE 296 24 638; World Patent Application Publications WO2006/087179, WO2006/081140, WO2006/087179, and WO2007/064580; and European Patents including EP 1 218 156 and EP 1 582 327. These patents and applications are all owned by the assignee and are included herein by way of reference in their entirety.
These disclosures remain silent as to the use of inserts in the pelletization process. More specifically, these disclosures remain silent regarding the use of inserts in the extrusion die, wherein molten material flows about the extrusion die and insert such that a hollow pellet is generated.
The various embodiments of the present invention provide a cost effective method to prepare reproducible hollow pellets by use of a multiplicity of inserts in an equivalent multiplicity of die orifices through an extrusion die plate.